Safe points are exported in a per-module list via the crate map. A C
runtime call walks the crate map at startup and aggregates the list of
safe points for the program.
Currently the GC doesn't actually deallocate memory on malloc and
free. Adding the GC at this stage is primarily of testing value.
The GC does attempt to clean up exchange heap and stack-allocated
resource on failure.
A result of this patch is that the user now needs to be careful about
what code they write in destructors, because the GC and/or failure
cleanup may need to call destructors. Specifically, calls to malloc
are considered unsafe and may result in infinite loops or segfaults.
Many changes to code structure are included:
- removed TIME_SLICE_IN_MS
- removed sychronized_indexed_list
- removed region_owned
- kernel_owned move to kernel.h, task_owned moved to task.h
- global configs moved to rust_globals.h
- changed #pragma once to standard guard in rust_upcall.h
- got rid of memory.h
See https://github.com/graydon/rust/wiki/Logging-vision
The runtime logging categories are now treated in the same way as
modules in compiled code. Each domain now has a log_lvl that can be
used to restrict the logging from that domain (will be used to allow
logging to be restricted to a single domain).
Features dropped (can be brought back to life if there is interest):
- Logger indentation
- Multiple categories per log statement
- I possibly broke some of the color code -- it confuses me
Apparently it can't live in the main binary, since on non-Linux
platforms, dynamics libs won't find symbols in the binary. This
removes the crate_map pointer from rust_crate again, and instead
passes it as an extra argument to rust_start. Rustboot doesn't pass
this argument, but supposedly that's okay as long as we don't actually
use it on that platform.
This overloads the meaning of RUST_LOG to also allow
'module.submodule' or 'module.somethingelse=2' forms. The first turn
on all logging for a module (loglevel 3), the second sets its loglevel
to 2. Log levels are:
0: Show only errors
1: Errors and warnings
2: Errors, warnings, and notes
3: Everything, including debug logging
Right now, since we only have one 'log' operation, everything happens
at level 1 (warning), so the only meaningful thing that can be done
with the new RUST_LOG support is disable logging (=0) for some
modules.
TODOS:
* Language support for logging at a specific level
* Also add a log level field to tasks, query the current task as well
as the current module before logging (log if one of them allows it)
* Revise the C logging API to conform to this set-up (globals for
per-module log level, query the task level before logging, stop
using a global mask)
Implementation notes:
Crates now contain two extra data structures. A 'module map' that
contains names and pointers to the module-log-level globals for each
module in the crate that logs, and a 'crate map' that points at the
crate's module map, as well as at the crate maps of all external
crates it depends on. These are walked by the runtime (in
rust_crate.cpp) to set the currect log levels based on RUST_LOG.
These module log globals are allocated as-needed whenever a log
expression is encountered, and their location is hard-coded into the
logging code, which compares the current level to the log statement's
level, and skips over all logging code when it is lower.
